This invention relates generally to pull-out sofa beds and is particularly directed to locking linkage for a foldable pull-out sofa bed.
Foldable couch/bed combinations frequently referred to as sofa beds, generally include moveable seat and back portions which can be folded to a seating configuration and unfolded to a horizontal, generally planar reclined configuration for use as a bed. Suitable linkage is provided for pivotally coupling the seat and back portions. In some sofa beds, the seat portion of the sofa unfolds outward from the back portion which remains fixed in position, with the distal end of the thus unfolded seat portion supported by unfolding legs. In others, the back portion of the sofa reclines to provide, with the seat portion, a pair of generally flat, aligned support surfaces. Other approaches make use of extendable/retractable frame extensions at either the head or foot portion of the unfolded configuration to provide additional support surface area.
To date, folding sofa bed combinations have suffered from various shortcomings. For example, the absence of means for locking the unfolded assembly in the bed configuration allows the flat support surface to be easily rendered non-planar when weight is concentrated on a relatively small surface area, particularly along a median axis of the bed such as between the unfolded seat and back portions thereof. Those sofa beds which require unfolding of the seat portion by pulling up on an aft, inner portion of the seat require considerable strength for unfolding. This precludes use of this type of folding sofa bed by the handicapped, feeble or those of advancing age. Finally, presently available pivoting linkage for folding sofa bed combinations is generally complicated and makes use of a large number of components which increases its cost and reduces its reliability and limits its usable lifetime.
The present invention addresses the aforementioned limitations of the prior art by providing a folding sofa bed which includes back, seat and extension portions moveable between a generally horizontal, planar array when in the bed configuration and a sofa configuration, wherein the back is oriented generally vertical and the seat generally horizontal, with the extension portion retracted to a position below a forward edge of the seat. Suitable coupling linkage allows for folding the back, seat and extension portions between the sofa and seat configurations and for maintaining the three aforementioned components in locked, or rigidly fixed, position when in either configuration.